How to Grow Cosmos: Planting Methods and Key Technical Points

Cosmos, also called autumn cosmos and gesang flower, is an annual or perennial herbaceous plant native to Mexico in the Americas, and it only became widely known after Columbus discovered the New World. Its scientific name Cosmos carries fine connotations in Greek such as harmony, order and good deeds. It is now also widely cultivated in China, and wild cosmos often grows beside roads or field ridges. In the flowering season it is very beautiful, its many colors catching people's eyes. So how should we grow cosmos?

1. Soil

Cosmos has rather particular soil requirements. Cosmos likes soil that is not too fertile, and it must not be fertilized too much during growth, otherwise the growth of cosmos will be hindered, causing excessive vegetative growth of branches and leaves and affecting the quality of flowering. If the cosmos plant grows too tall, it will fail to bloom or produce very few flowers, reducing its ornamental value.

2. Sowing

First put the prepared cosmos seeds in a small plastic bag, then place the seeds in a dry, cool place to keep them fresh. The suitable growing temperature for cosmos is generally around 25°C, and the season that usually reaches this temperature is spring, so we can sow in March and April. Choose a flower pot of suitable size, bury the cosmos seeds 3 to 5 cm below the soil surface, then cover with a thin layer of soil. After sowing, water the soil thoroughly once, and finally place the pot in a cool place to wait for the cosmos seeds to germinate. When the temperature is above 15°C, cosmos generally begins to sprout in about a week. The sprouted cosmos can be moved to a sunny place, but be careful not to expose it to strong direct sunlight; let the cosmos seedlings gradually adapt to the light.

3. Light

Cosmos likes sunlight and can withstand drought; it is a short-day plant.

4. Pinching

Spring-sown cosmos seedlings often have lush leaves but few flowers, while summer-sown seedlings are short, neat and bloom continuously. Cosmos grows very fast, and during growth we can pinch it back several times, which promotes the growth of its branches. Generally, during the growing period of cosmos, cut back the tips of the central branches appropriately to encourage cosmos to produce more flowers.

5. Watering and Fertilizing

Cosmos tolerates poor soil, but soil with standing water must be avoided. It does not adapt to the high temperatures of summer, nor can it withstand the severe cold of winter; it dislikes both scorching heat and cold environments, and likes loose, breathable soil with good drainage. If you want to fertilize it, the best method is to mix the fertilizer with water, stir it evenly, and then pour it into the soil in liquid form.